Нижний блок: 1. 1/3 + 0,5; 2. 5/6 − 0,25; 3. 0,4 · 2/3; 4. 0,75 : 3/8; 5. 7/9 + 0,2; 6. 1,5 · 2/9.

1. \(\frac{1}{3}+0{,}5=\frac{1}{3}+\frac{1}{2}=\frac{2}{6}+\frac{3}{6}=\frac{5}{6}\).
2. \(\frac{5}{6}-0{,}25=\frac{5}{6}-\frac{1}{4}=\frac{10}{12}-\frac{3}{12}=\frac{7}{12}\).
3. \(0{,}4\cdot\frac{2}{3}=\frac{2}{5}\cdot\frac{2}{3}=\frac{4}{15}\).
4. \(0{,}75:\frac{3}{8}=\frac{3}{4}\cdot\frac{8}{3}=2\).
5. \(\frac{7}{9}+0{,}2=\frac{7}{9}+\frac{1}{5}=\frac{35}{45}+\frac{9}{45}=\frac{44}{45}\).
6. \(1{,}5\cdot\frac{2}{9}=\frac{3}{2}\cdot\frac{2}{9}=\frac{1}{3}\).

Ответ: 1) \(\frac{5}{6}\); 2) \(\frac{7}{12}\); 3) \(\frac{4}{15}\); 4) 2; 5) \(\frac{44}{45}\); 6) \(\frac{1}{3}\).